In vehicular applications, a typical four-wheel steering system steers the front and the rear wheels of a vehicle. More specifically, a rear-wheel steering portion of the system may produce a desired rear-wheel steering angle to improve maneuverability at low speeds. The low speed steering method may achieve tight turning radii at low speeds by steering the front and rear wheels in different directions to thereby reduce the effective turning radius of the vehicle.
In the rear-wheel steering portion of a four-wheel steering system, an electric motor is typically employed to steer the rear wheels. The position of the rear steering mechanism may be determined with a sensor and, as aforementioned, is positioned with reference to the vehicle speed. It may be desirable to provide a vehicle speed diagnostic mode that retains the many benefits of four-wheel steering while compensating for the presence of any irregularities in vehicle speed signals than can cause an unintended steering in the vehicle.
The above described and other features are exemplified by the following Figures and Description in which a vehicular speed diagnostic algorithm is disclosed that validates a signal indicative of a speed of a vehicle by receiving a plurality of signals indicative of vehicle speed; correlating at least a first of the received signals with at least a second of the received signals to determine if either signal is invalid; and signaling a rejection of any signal found to be invalid.